5:30 pm

Thu November 15, 2012

In Sandy's Wake, A Reshaped Coastline

Sandy punched a hole in the barrier island that holds the affluent borough of Mantoloking, N.J., temporarily splitting the community in two. The storm also destroyed several multimillion-dollar homes and erased the island's protective system of dunes.

New Jersey's most affluent community, Mantoloking, sits on a narrow barrier island 30 miles north of Long Beach. As Sandy approached, most of the residents fled inland. But Edwin C. O'Malley and his father, Edwin J. O'Malley Jr., hunkered down in their 130-year-old house.

They tied a boat to their porch and then watched the storm surge break over the dunes and flood the streets.

"Overnight that night, lying in bed, I could actually hear waves hitting the side of the house — which obviously made it more difficult to get to sleep," the younger O'Malley says.

The ocean entered the O'Malleys' living room and rose to the height of their couch cushions. It crept higher than the water level during the 1992 nor'easter, higher than the 1938 hurricane, higher than any storm in either man's memory. When the water retreated, the O'Malleys had escaped with minimal damage. Other homes weren't so lucky.

"When the weather finally cleared, looking out of the east side of the house towards the ocean, where we would normally see houses or trees blocking our view, we could see breaking ocean waves," O'Malley says. "At that point we knew houses were gone."

And Sandy didn't just completely flatten several of Mantoloking's multimillion-dollar beach-side houses — it reshaped the beach itself.

"Those dunes were 100 percent gone," O'Malley says. "Some of that sand, of course, got sucked out into the ocean, but a lot of it got pushed into town. There were sand dunes on the streets in some places that were a couple of feet thick. And my father and I walked the dogs through the center of town over huge piles of sand right in front of the post office and police station."

It was a bizarre scene repeated in communities up and down the Atlantic coast — a testament to the reach of the storm.

"For my career this was the largest storm I've ever witnessed," says Cheryl Hapke, a scientist at the United States Geological Survey. "[It's] the most coastal change I've seen from a single event."

Hapke is a part of team trying to measure Sandy's coastal impact. Before and after the storm, team members followed the coastline in a low-flying plane, collecting a series of photos and topographical data.

The images show entire islands sliced into pieces, destroyed harbors full of scattered boats, and the remains of an amusement park.

And everywhere, the coastline has receded. The ocean moved inland, pushing the dunes in front of it. It will take a few weeks to figure out just how much sand has been moved, but the USGS has some early measurements from Fire Island, N.Y., a narrow strip of land between Long Island and the Atlantic.

Two days before Sandy hit, Hapke visited Fire Island to survey the dunes. Once the storm had passed, she returned by boat with a few National Park Service rangers.

"We got out there not knowing what to expect," Hapke says. "And it was just, again — I use words like amazing and astounding how much change had occurred."

At the height of the storm, nearly half of Fire Island was underwater. Some dunes lost 10 feet of elevation, and the change in the coastline was dramatic.

"The whole of the island on average, it moved back 72 feet, which is huge," Hapke says. "I mean if your house is there, it's gone."

Hapke says that beaches farther south have probably experienced even greater changes, but she adds that nature's healing process has already begun. The sand that was pushed inland will naturally regenerate dunes in their new location.

But Hapke says that can cause problems. People don't want dunes in their street — they want to rebuild the beach back where it once was.

"But basically [the beach] doesn't want to be there — it wants to move as sea level rises," Hapke says. "So the more we put it back, the more likely it is to experience this kind of impact in another severe storm."

That raises a question that's sure to be debated as the East Coast recovers from Sandy: Should everything be rebuilt just as it was before?